Marwin Valve UT Series Pneumatic Actuators - Manual (Page 5)

Assembly
1. Clean the components before proceeding with the assembly.
2. Lightly grease the internal chamber of the body (1) and the seals on the pistons. We suggest the use of an
extreme pressure lithium based grease such as Kluber Centoplex 2 EP.
3. Carefully insert the pinion (2) into the body (1), so that the two pinion flat surfaces are parallel to the axis of the
body and secure with spacer ring (5) and pinion snap ring (6).
4. Insert the pistons (pre assembled and greased) into the body as shown here below.
5. Push the pistons (7) into the body (1) until the piston teeth are stopped by the teeth of the pinion (2).
6. Keeping a soft pressure with the hands on the pistons (7), rotate the body (1) in clockwise rotation in respect to
the pinion (2) until feeling two clicks, when the pistons engage with the pinion (2).
7. Now rotate the body (1) in counterclockwise rotation, and verify that at the end of the rotation the two pinion
flat surfaces are at right angles to the axis of the body.
NOTE: Correct assembly gives symmetric stroke of the pistons, which can be verified by measuring distance
from each end face of the body. These distances should be equal.
FOR DOUBLE ACTING ACTUATORS
8. Assemble the end caps (18,19) to the body (1) with the screws (20), using a diagonal bolting pattern.
FOR SPRING RETURN ACTUATORS
9. With the pistons in the CLOSED position, insert the springs in spring set (M) into the body (1), putting them
in the piston (7) recess. Then assemble the end cap (18,19) on the springs. Center the end cap recess on the
springs. Assemble the screws (20), using a diagonal bolting pattern to tighten each screw a little at a time, so
that the springs are uniformly compressed, until end cap (18) is completely closed. Note: A press and guard
are suggested for performing this operation on actuator sizes UT-5 and UT-6.
10. Repeat the operation on the other side.
11. Operate the actuator to verify the correct functioning before re-installing it.
-5-
Assembly Possibilities - Top View
Counterclockwise Rotation (Standard) Clockwise Rotation (Reversed Pistons)
Closed Closed Open Open